Auditing and Accountability for AWS S3 Read-Only Roles
The bucket looked empty, but it wasn’t.
Inside an AWS S3 bucket, hundreds of files sat untouched—for months, maybe years. Read-only roles had access. Nobody noticed who was reading them, when, or why. The audit logs told a story, but only if you knew where to look.
Auditing AWS S3 read-only roles is not just a compliance checkbox. It’s a control point. Misconfigured permissions and gaps in monitoring can leak sensitive data without anyone writing a single line of delete code. Data loss is not always about destruction. Sometimes it’s about quiet, invisible access.
The first step is identifying every IAM role with read-only permissions on your S3 buckets. Start by listing all current role policies. Pay close attention to policies granting s3:GetObject, s3:ListBucket, and wildcard actions like s3:* under read-only contexts. This is how internal overreach and unexpected external sharing start.
Once roles are mapped, connect CloudTrail to track activity at a granular level. Filter for GetObject events and correlate them with role and bucket. Do not rely on last-modified timestamps for files; these will not reveal unauthorized reads. True accountability depends on event-by-event visibility.
Use bucket policies and IAM conditions to enforce access from approved sources. Limit the blast radius with resource-based policies that tie into your AWS Organization’s SID identifiers. Make sure any audit trail is immutable, exportable, and correlated with timestamps accurate to the second. Every second matters when tracing anomalies.
Regularly compare real access patterns against your policy intent. A read-only role granted for a single backup integration three months ago should not still be touching files daily. The only way to know this is to measure, log, and review.
This level of auditing and accountability builds trust across your systems. It means you can show, without doubt, who accessed what and when. It also means you have the discipline to act when something is wrong—before it becomes a breach.
You can get this visibility live in minutes with hoop.dev. Connect it, set your scope, and see exactly how your S3 read-only roles behave—not weeks from now, but now.